Strangely hypnotic 1930 silent film produced by Chas. F. Herm, "Cinema Biologist" of Daytona Beach. Demonstrates the use of rabbits to determine if a sample of blood is of human origin, through their production of antibodies. Includes a shot of a rabbit with a sign in front of it reading "Anti-Human". Also a nurse who apparently transfers blood samples from one place to another by sucking them into a straw.
This would probably work well with some early Pink Floyd in the background...if you know what I mean.

p.s. Hello Roland!

(oops I forgot to review this.. thanks Traf! ;) )

The weirdly titled Preciptins takes us to the 1920's lab where people are looking for cures for all sorts of diseases, but right now, they're working on simple things, like how they can tell if a blood sample is from a human or not. A nurse (wearing an impressive 20's hairdo I must say) takes the blood from a rabbit and somehow we all find out that the blood sample we had, yes, DID come from a human. How this was figured out still is a blur to me.